Oven window construction



Nov. 5, 1968 G. A. KOCHANOWSKI 3,408,785

OVEN WINDOW CONSTRUCTION Filed Oct. 15, 1965 2 Sheets-Sheet 1 (J44, W, Kant L04...

UhTomsx/ Nov. 5, 1968 G. A. KOCHANOWSKI 3,408,785

OVEN WINDOW CONSTRUCTION 2 Sheets-Sheet 2 Filed Oct. 15, 1965 George CA .qfiocaflouni CATTORMEY/ ABSTRACT OF THE DISCLOSURE A fog-resistant window construction for ovens is described which utilizes rounded bezels, square glass plates,

and a flexible circumferential one-Way sealing gasket which provides both a seal against the entry of moisture and a self-clearing effect when the oven is used.

This invention relates generally to window assemblies for ovens and the like, and more particularly concerns an improved heat-insulating oven window assembly.

In ovens of the type found in domestic kitchens, a window is often incorporated into the oven door to allow the cooking process to be observed. Such a window must, of course, be insulated to prevent the escape of heat from the oven, and it must maintain its transparent qualities through repeated heating and cooling cycles as the oven is used. The most common technique used in construction of such windows is to employ a double window comprising two panes of glass which are spaced apart to define an airspace which serves as insulation.

' Heretofore, a disadvantage of this construction was that the windows would sometimes become fogged on their inaccessible inner surfaces. Cooking of food in or near the oven and the normal use of hot water in the kitchen would create quantities of water vapor and steam which would tend to enter the air space between the panes and would condense on the inner surfaces of the window when the oven was cooled to form a fog, thereby ruining the transparency of the window and detracting from the appearance of the oven itself.

It is therefore a primary object of the present invention to provide an oven window assembly of improved construction which is resistant to fogging from the condensation of water vapor on its inner surfaces, and which will tend to rid itself of such condensation during the normal use of the oven.

Another object is to provide an anti-fogging oven window assembly which is of simplified and economical construction and which may be quickly and easily assembled and installed on a production line.

A further object is to provide an anti-fogging oven window construction having generally rounded exterior corner contours for presenting a pleasing appearance, yet which is capable of utilizing economical square-cornered rectangular sheets of glass.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a perspective of an oven door incorporating the oven window of the present invention;

FIG. 2 is a fragmentary section taken through the plane 2-2 in FIG. 1;

Patented Nov. 5, 1968 FIG. 3 is a fragmentary section taken through the plane 3-3 of FIG. 1;

FIG. 4 is a perspective of the closure plate illustrated in FIG. 2;

FIG. 5 is a fragmentary section of the corner construction of the window taken through the plane 5-5 of FIG. 3;

FIG. 6 is a fragmentary section similar to that of FIG. 5, taken through the plane 6-6 of FIG. 3;

FIG. 7 is a perspective of an assembled oven window constructed according to the invention;

FIG. 8 is an enlarged section of the inner frame shown in FIG. 3;

FIG. 9 is an enlarged section of the rubber gasket shown in FIG. 3; and

FIG. 10 is a perspective of the outer frame of the oven window illustrated in FIG. 7.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment, but intend to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims.

Turning now to the drawings, in FIG. 1 there is shown an oven door 10 embodying a window 11 constructed according to the present invention. The window 11 is an assembly which is fabricated and assembled separately ,to be installed as a unit in the oven door 10.

The window assembly 11 comprises two plates of heatresistant transparent glass, 12, 13, separated by an inner frame or spacer 15 which extends generally around the periphery of the outline of the glass plates 12, 13. The spacer 15 is sandwiched between the glass plates 12, 13 to form an air space 16 within the hollow of the spacer 15 and enclosed by the glass plates 12, 13. The air space 16 provides insulation for the oven window assembly 11 by reason of the low heat conductivity of the entrapped air.

In accordance with the invention, the assembly 11 includes a gasket 25, defining a one-way valve opening from the air space 16, and a frame 17 that holds the assembly 11 together and defines decorative rim or bezel portions 30, 31 on both sides of the window 11. The gasket 25 is concealed, supported and held in sealing relationship with the glass plates 12, 13 by the spacer 15. For this purpose, the spacer 15 is a generally flat band bent into a rectangular shape with a pair of ridges 18 and 19 formed at each edge so as to extend outwardly and run peripherally about the spacer. Thus, when sandwiched between the glass plates 12, 13 (see FIG. 8), a pair of annular channels 20 and 21 are defined along the lines of contact with the glass.

The gasket 25 is preferably fabricated as an endless belt of flexible, elastic material such as silicone rubber which is suitable for high temperature applications, and has a pair of O-ring like beads 22 and 23 connected to the body of the spacer by convolutions 26 and 27, respectively, that match the general outline of the spacer ridges 18, 19 (see FIG. 9). The gasket '25 is assembled with the spacer 15 by being expanded slightly about the spacer with the convolutions 26, 27 snugly fitting about the ridges 12, 13 and the beads 22, 23 wedged in the channels 20, 21 where they engage the glass in air-tight sealing relationship (see particularly FIG. 3).

The frame 17 is the third main element, along with the spacer 15 and the gasket 25, which cooperates with the glass plates 12, 13 to make up the window assembly 11. The frame 17 (see FIG. is a generally rectangular structure having decorative inner and outer bezel portions 30 and 31 with rounded corners and joined by connecting webs 32, 33 and 35 to form inwardly opening channels sized to embrace the glass plate and spacer sandwich (see FIG. 3). Preferably, the bezel portions 30, 31 and the webs 32, 33, 35 are formed integrally from a single strip folded into rectangular shape with the strip ends joined by a spot welded tab 37 to define an annular unit. The end of the frame 17 having no connecting webis closed by a channel-like closure plate 36 having slots 39 which receive tabs 38 extending from the open end of the bezel portions 30, 31 (see FIGS. 4 and 10). Withthe plate 36 in place and the tabs 38 folded over, the plate defines the fourth side of the annular frame 17 which holds the assembly 11 together.

i The open corners between the two webs 32, 33 and the web 35 and the plate 36, permit economical rectangular glass plates 12, 13 to be used while retaining the desirable rounded corner appearance of the bezels 30, 31. The square corners of the glass simply project from the corners of the frame 17. Also, before the plate 36 is locked in place, the glass, spacer and gasket sandwich can easily he slid into the open end of the frame 17 making assembly rapid and convenient.

As so assembled, it can be seen that the spacer completely conceals the gasket from view through the window so that the completed assembly 11 presents a neat appearance. Also, the configuration of the gasket beads 22, 23 and the channels 20, 21 prevent the leakage of gas from the atmosphere into the air space 16, but permit leakage in the other direction. If the pressure of the atmosphere is greater than that within the air space 16, the force of the pressure differential tending to drive air through the joint between the spacer 15 and the plates 12, 13 will tend to press the beads 22, 23 more tightly into their channels 20, 21, and thereby increase the effectiveness of the seal. A pressure differential acting in the opposite direction, however, will tend to drive gas into the channels 20, 21 through the joint where the spacer 15 abuts the plates 12, 13. Pressure in this direction tends to unseat the beads 22, 23 and the leakage is thereby allowed to escape into the atmosphere.

The seal formed by the gasket 25 thus acts as a oneway valve, allowing the escape of gas from the air space 16 but blocking the reentry of gas into that area should the pressure differential be reversed. This feature has the desired effect of making the window assembly 11 fogresistant, because any moisture accumulating within the window assembly 11 will tend to be driven out each time the window 11 is heated during normal use of the oven. With the air within the air space 16 at atmospheric pressure, such as would be the case after initial assembly, let us assume that some moisture has condensed in the form of fog on the inner surface of one of the glass plates 12, 13. When the window assembly 11 is installed in the oven, the first use of the oven will heat the window 11 and with it the air and condensed moisture within the air space 16. As the temperature within the air space rises, the condensed moisture will tend to be vaporized as its vapor pressure is raised by the increasing temperature. This effect is especially true for the plate 12, the inside pane of the window, because this plate of glass will be at substantially the oven temperature.

As the temperature of the air and water vapor within the air space 16 rises, its pressure is also increased as a function of the increase in temperature. As a pressure differential is built up, leakage of air and water vapor through the joint between the spacer 15 and the glass plates 12, 13 unseats the beads 22, 23 of the gasket 25 and a quantity of the air and water vapor escape from the air space 16. Thus, a portion of the moisture that had previously existed as condensation within the window assembly 11 is thereby removed. When the oven is turned off, the temperature of the window 11 gradually decreases, and the pressure within the air space 16 is reduced accordingly. Because configuration of the gasket 25 within the channels 20, 21 acts as a one-way seal, air and moisture cannot reenter at the airspace 16, even though its pressure will drop below that of the atmosphere. In fact, a positive pressure differential between the atmosphere and the air space 16 tends to enhance the effectiveness of the seal by wedging of the beads 22, 23 into the channels 20, 21, and preventing the reentry of moisture into the interior of the window assembly 11.

In time, as the oven is allowed to cool between uses, it is possible that some air will leak past the seal made by the gasket 25 into the air space '16, and the pressure within the window assembly 11 will again approach that of the atmosphere. In this event, the air that will have reentered the air space 16 will be likely to be dryer than that which was originally driven out, because the relatively large amounts of steam and water vapor present during cooking and dishwashing operations in the kitchen are not likely to be continuously present during the long period required for air to leak past the seal and reenter the air space 16. Further in accordance with the invention, any air so :reentering will again tend to be driven off the next time the oven is used, carrying with it an additional quantity of moisture. Thus it may be seen that the one-way seal of the gasket 25 makes the window assembly 11 not only fog-resistant, but also self-clearing to a substantial degree because of the tendency during each oven operating cycle to purge the air space 16 of an additional quantity of moisture.

Installation of the window assembly 11 in the oven door 10 is accomplished by the provision of threaded mounting brackets 40 which are slipped into corresponding slots 41 in the web 35 and the plate 36 of the frame 17. The brackets 40 may be of any suitable construction, and in the preferred embodiment are Tinnerman nuts, of the sort commonly used in oven construction. The window 11 is secured to the oven door 10 by bolts 42 which extend through the back of the door 10 and engage the threaded portions of the mounting brackets 40, thereby clamping the rear bezel 31 of the window assembly 11 to a corresponding ledge at the rear of the oven door 10. The back and front panels of the door 10 are preferably apertured and shaped to blend with the bezels 30, 31 of the window assembly 11.

Advantages of this construction include the use of inexpensive square-cornered glass plates 12, 13, while preserving the esthetic features of rounded bezels 30, 31 for a pleasing appearance of the finished window assembly 11. The use of rolled stock for the outer frame 17 as well as the spacer 15 has additional advantages of inexpensive and sturdy construction. The one-piece gasket 25 with sealing beads 22, 23 is also positively and securely held in place by the ridges 18, 19 on the spacer 15, so that no misalignment can occur during assembly or use of the window 11.

I claim as my invention:

1. The method of preventing condensation of moisture in an oven window having two transparent plates spaced apart to define an air space comprising the steps of allowing air and water vapor within said air space to heat and expand as the oven window becomes heated in normal use, allowing said heated and expanded air and water vapor to escape from said air space, and sealing said air space against the re-entry of air or water vapor as said oven window is again cooled after said use, the foregoing steps being repeated each time the oven is used to thereby drive out any leakage that may have entered said air space between uses.

2. In an oven window having inner and outer transparent plates separated by a peripheral spacer abutting the inner surfaces of said plates and said Window being secured together by a frame to define an enclosed air space, the improvement comprising a cross-sectional external convolution on said spacer peripherally disposed adjacent the abutment between said spacer and said transparent plates, and a resilient deformable gasket having a convolution of similar cross-section adapted to position said gasket against said abutment in sealing relationship with respect to leakage irom the atmosphere into said air space.

References Cited UNITED STATES PATENTS 2,612,154 9/1952 Mills s 126-200 2,620,522 12/1952 Fish 52-399 6 3/1959 Schibley 126-200 1/1960 Blaszkowski 52-399 2/1965 Moss 126-200 11/1965 Larkin 52-398 4/ 1966' Buck 52-304 FOREIGN PATENTS 1963 Canada. 1964 Canada. 1964 Great Britain.

FRANK ABBOTT, Primary Examiner.

2 724 73 11 1955 Cameron 52 399 15 Assistant Examiner 

